Slow thaw foils forecast

Flood season pushed into May

The water is coming, that much we know for sure. Now it's just a matter of when and how much.

And the slowness of the spring thaw has left the answer to that key question as clear as Red River mud.

TIM SMITH / BRANDON SUNSUN

Manitoba Infrastructure and Transportation workers put super sandbags into place along the west side of 18th Street in Brandon Friday.

"It's not taking a lot of the snow out," Emergency Measures Organization Minister Steve Ashton said of the slow melt at Friday's flood outlook briefing. "There's a lot of snow that's still out there in rural Manitoba that's not really impacted by even what's taken place now."

The forecast now calls for colder weather to continue into the next month with the spring thaw to finally take hold sometime in the first week of April.

It's the pace of that melt and how much more snow or rain falls, on both sides of the border, that will determine the extent of spring flooding in the Red River Valley, the Assiniboine River and other rivers and streams in southern Manitoba.

In North Dakota, the National Weather Service on Friday raised its spring flood forecast by a foot due to rain and snow that fell on the state earlier this week.

Because of that, Manitoba's flood forecasters are now predicting, with average weather, that flooding in the Red River Valley will be "slightly higher" (1.3 feet to 2.3 feet) than in 2009, the fourth-worst flood on record. If we get hit by bad weather over the next three weeks, flood levels could approach what was seen during the 1997 Flood of The Century when much of the valley was under water.

"It's not only precipitation," provincial flood forecaster Phillip Mutulu said. "It's also how fast that snow is going to melt."

The cold weather will also likely extend flood season into early May with the flood crest to hit Winnipeg likely in late April, about 10 days to two weeks after it passes through Fargo., N.D.

"There's a lot of time ahead," Ashton said. "We have a fairly long window here for flooding. We're going have to watch the weather very closely. It's certainly a significant element right now."

Flooding is also expected along the Souris River, the Pembina River and the Fisher River, the degree depending on weather and rate of the spring thaw.

"We are clearly looking at the high potential for flood," Ashton said. "That's why we're in a high state of alert and prepared."

One thing not expected to be a factor this year is river ice jams. Crews have finished smashing more than 30 kilometres of ice north of Selkirk to the mouth of Lake Winnipeg to ease the flow of ice and floodwater in to Netley Marsh. Cutting is now taking place on the Whitemud River and the Icelandic River at Riverton. Work is also taking place on the Brokenhead River, the Portage Diversion and soon on the Fisher River and Assiniboine River near Glenboro.

More than 230 pieces of heavy machinery are continuing work on a new 112-km clay dike on the Assiniboine River between Portage la Prairie and Elie. It will be finished before the river crests in mid-to-late April.

South of border

The National Weather Service released a new flood forecast for North Dakota Friday, raising its spring crest prediction for the Red River by more than a foot at Grand Forks and Fargo.

Fargo-Moorhead

The new outlook shows a 20 per cent chance the river will go to 43.3 feet, a 50 per cent chance the river will reach 40.5 feet, a number that would nearly match the record 2009 crest of 40.84 feet, and an 80 per cent chance the river will rise to 38 feet. Last year, the Red River in Fargo crested just below 37 feet.

Grand Forks-East Grand Forks

There's a 20 per cent chance the river will go 53.9 feet, a 50 per cent chance of the Red going to 51.9 feet, which would be the city's second-highest level on record, behind the 54.35 feet crest on April 22, 1997,and an 80 per cent chance the river will go to 50.3 feet.

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